The 2016 Nobel Prize in Physiology or Medicine recently went to Yoshinori Ohsumi for his discoveries into the mechanisms of autophagy. Also known as 'self-eating', autophagy is the process in which cells degrade and recycle their components.

Dr Ohsumi's research studied the genetic makeup of yeast to discover the genes involved in this cellular activity and his work has already led to a better understanding of diseases such as cancer, Parkinson's and type 2 diabetes.

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Dr David Reynolds, chief scientific officer at Alzheimer’s Research UK, said Dr Ohsumi's contribution to research is "fundamental" to treating diseases like Alzheimer’s.

He added: “We’re now funding research to better understand faulty waste disposal in Alzheimer’s and teams in our Drug Discovery Alliance are working to design drugs for dementia that boost autophagy and other waste disposal systems – progress which would not be possible without the essential foundations laid by Dr Ohsumi.”

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Below, we explain what autophagy is and why Dr Ohsumi's work is so important for modern medicine.

What is autophagy?

Autophagy (illustrated) provides fuel for energy and building blocks for renewal of cells. After infection, autophagy can destroy bacteria and viruses and it contributes to embryo development as well cell differentiation

Nobelprize.org

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The word autophagy comes from the Greek for 'self' and 'phagein', which means 'to eat'. During the 1960s, early work into this field discovered that cells could destroy their contents before being degraded, in an area called lyosome.

Each of our cells have separate, specialised compartments. The lysosomes contain the enzymes needed to digest the contents of the cell such as proteins and organelles. Organelles are parts of the cells containing enzymes that digest proteins, carbohydrates and lipids.

A type of vesicle or sac, called autophagosome, forms and 'eats' these contents before combining with the lysosome to degrade them into smaller pieces. This gives the cells nutrients to help it renew.

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Put more simply, autophagy provides fuel for energy and building blocks for renewal of cells. After infection, autophagy can destroy bacteria and viruses and it contributes to embryo development as well cell differentiation.

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Elsewhere, cells use autophagy to get rid of damaged proteins and organelles, a so-called "quality control mechanism" necessary to counteract the negative effects of ageing on the body.

What did Dr Ohsumi discover?

As part of Dr Ohsumi's initial research, he used yeast to identify the genes that are responsible for autophagy and how this technique is similar in our own cells.

In 1988, he particularly studied how proteins degraded in a region called the vacuole, an organelle that corresponds to the lysosome in human cells. Ohsumi proposed that if he could disrupt the degradation process in the vacuole, while autophagy was taking place, autophagosomes should build up within the vacuole and become visible under the microscope.

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He cultured yeast that lacked these vacuolar degradation enzymes, which in turn 'starved' the cells and kickstarted the autophagy process.

Building on this research, Ohsumi used these mutated strains of yeast to suggest that genes could be responsible for naturally kickstarting autophagy in non-engineered samples and, using a chemical to add mutations to the genes, he was able to identify those involved.

Later research characterised the proteins and protein complexes in these genes and revealed that each stage is governed by a distinct selection of these proteins.

Why is this work so important?

Changes and so-called 'disrupted' autophagy have been previously linked to Parkinson's disease, type 2 diabetes and other diseases and disorders that typically affect the elderly. They have also been linked to cancer. In particular, mutations in the autophagy genes identified thanks to Dr Ohsumi's work can lead to genetic disease.

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This means Ohsumi's discoveries led to a new way of understanding how our cells recycle their content. Drug trials are ongoing, using Dr Ohsumi's work, into treating the diseases mentioned.

Why did the Nobel Prize committee choose Dr Ohsumi's work?

In a statement, the prize committee said: "Thanks to Ohsumi and others following in his footsteps, we now know that autophagy controls important physiological functions where cellular components need to be degraded and recycled.

"Autophagy has been known for over 50 years but its fundamental importance in physiology and medicine was only recognised after Yoshinori Ohsumi's paradigm-shifting research in the 1990's. For his discoveries, he is awarded this year's Nobel Prize in physiology or medicine."